Classic schwannoma showing Antoni A and Antoni B regions (photomicrograph)

Classic schwannoma demonstrating biphasic architecture composed of Antoni A and Antoni B regions. Antoni A regions are characterized by dense, compact rows of elongated, spindle-shaped cells with rod-shaped nuclei and eosinophilic cytoplasm (lower left). Antoni B regions are loosely organized and contain large, vacuolated, stellate cells with areas of microcystic change and lipid accumulation (upper right). (Hematoxylin-eosin; x132) (Contributed by Dr. Herbert Newton.)